Air-compressor



E. L. BLEVINS.

AIR COMPRESSOR.

Prue/mon mtu was. |920.

Patented Oct. 18, 1921.

2 SHEETS-SHEET 1.

N. mm mw/m mw I ll E. L. BLEVINS.

AIB COMPRESSOR.

Armcmou man Aus.a.192o.

Patented Oct. 18, 1921.

2 SHEETS-SHEET 2.

IN1/ENTR UNITED STATES PATENT OFFICE.

AIR-COMPRESSOR.

Specification of Letters Patent.

Patented Got. 18, 1921.

Application led August 3, 1920. Serial No. 400,932.

T o all whom iti/mcy concern.:

Be Yit known that I, EMORY LEE BLnvINs, a citizen of the United States, residing at Pattonhill, in the county of McCone and State of Montana, have invented new and useful Improvements in Air-Compressors, of which the following is a speciiication.

rllhis invention relates to pumping devices, particularly to air compressors, and has for its object the provision of an air compressor including a cylindrical body or shell within which reciprocate, at different speeds, separate plungers arranged in parallel relation and carrying pistons, the movement of one set of pistons with respectto the other compressing the air between them and forcing it out through the discharge ports in the end portions of the shell.

An important object is the provision of a device of this character which is provided with gear driven means for driving the different pistons, the pistons being formed with rack teeth engaging the gears.

Another object is the provision of a device of this character which will be comparatively simple and inexpensive in manufacture, highly efficient in use, positive in action, durable in service, and a general improvement in the art.

Vith the above and other objects and advantages in view, the invention consists in the details of construction to be hereinafter more fully described and claimed, and illustrated in the accompanying drawings in which- Figure 1 is a side elevation of the device,

Fig. 2 is a longitudinal sectional view taken in a vertical plane,

Fig. 3 is a horizontal longitudinal sectional view,

Fig. 4 is a cross sectional view on the line 4-4 of Fig. 2,

Fig. 5 is a cross sectional view on the line 5-5 of Fig. 2, and

The remaining five figures are detail views.

Referring more particularly to the drawings, the numeral 10 designates a cylindrical shell which is formed of a plurality of sections 11 which are similar and which are bolted together, being provided with the usual {ianges for the purpose. At their outer ends the shell sections 11 are closed by heads 12 and these heads are provided with outlet ports 13 surrounded by nipples 14 which are connected by an outlet manifold 15 having a discharge pipe 16 leading therefrom. Intermediate its ends, the shell 10 is formed with au inlet opening 1T.

Disposed longitudinally of the shell and slidable through one head 12, is a piston rod 18 which carries pistons 19 to be recipro- Cated within the shell. The end of the piston rod projecting from the shell may be connected with any suitable mechanism whereby t0 effect reciprocation thereof. It will be observed that the pistons 19 are designed to cooperate with the heads 12 for compressing air into spaces between these pistons and the heads. Each piston 19 is provided with a port 20 having a valve scat 21 normally closed by a spring-pressed valve 22 which is capable of opening outwardly, that is toward the heads 12.

Also disposed within the shell is a relatively short piston rod 23 carrying pistons 24 which are formed with holes 25 for the passage of the piston rod 18 and these pistons 24 are designed to coperate with the pistons 19 for compressing air between the pistons 24 and 19. The pistons 24 are formed with ports or passages 26 having valve seats 2T normally closed by springpresscd valves 28 which open outwardly, that is toward the pistons 19. It should be stated in passing that all the pistons 19 and 24 are provided with the usual or any proper packing rings such as are commonly employed ior such purposes.

Therpiston rods 18 and 23 have formed thereon racks 29 and 30, respectively, and these racks mesh with pinions 31 and 32, respectively, secured upon the shaft `iournaled transversely of the shell at its central portion. Disposed within the upper portion of the shell immediately above the piston rods 1 8 and 23, is a partial partition 34 adapted to be engaged by the piston rods in the event of buckling of the latter whereby to maintain the piston rods always with the racks thereon meshing with the associated pinions. Owing to the fact that the pinions 31 and 32 are of different diameters, it Will be obvious that the piston rod 23 and the pistons 24 carried thereby, will move at a different speed from the piston rod 18 and the pistons 19 thereon, this difference in speed being necessitated by the fact that the pistons have different strokes.

In the operation of the device, power is applied to the iston rod 18 to reclprocate the pistons 19. wing to the engagement of the rack 29 on the piston rod 18 with the pinion 31, the shaft and consequently the pinion 32 will also be rotated and this rotary Inove- Inent of this latter mentioned pinion will cause reciprocation of the piston rod 23 and pistons 2l. It will therefore be seen that all the pistons will reciprocate within the shell but that there will he relative-movement loetwecn thc pistons 1S) and 24. As either piston Ll moves toward the end of the shell, air will be sucked in through the port 17. At the same time any air between the outwardly moving piston 24 and the adjacent piston 19 will he compressed and will pass through the passage 2U, unseating the valve 22 therein so that this compressed air will get in advance of' the piston 19. As the piston 19 is also moving at the same time. thc air will be forced out through the outlet 14 into the manifold 15 and thence into the discharge pipe 16. On the return stroke the valves 22 and 2S will unseat so that air in advance of the pistons when moving in this direction will pass through the pistons and be compressed between the pistons and pass through the outermost piston 19 into the adjacent end of the casing or shell. As this movement continues first in one direction and then in the other, it will he obvious that air will he continuously drawn in, compressed between the pistons, and be forced out to wherever its use is needed.

From the foregoing description and a study of the drawings it will be apparent that I have thus provided a comparatively simply constructed and easily operated air compressor which will apidly compress air owing to the provision of the differential pistons having relative movement. It is apparent that the quickness of the compression is dependent mostly upon the fact that douhle compression is obtained at both strokes.

Thilo I have shown and described the preferred embodiment of my invention. .it is of course to be understood that I reserve the right to make such changes in the form, construction, and arrangement of parts as will not depart from the spirit of the invention or the scope of the suhjoined claims.

Having thus described my invention, I claim:

1. A device of the character described cornprising a cylindrical shell provided intermediate its ends with an air inlet opening and provided adjacent its ends with outlet openings, a power driven reciprocatory piston rod within said shell, pistons secured upon said rod and provided with outwardly opening spring-pressed valves, a second piston rod within the shell, pistons on said second named rod and positioned appreciably closer to ether than said first named pistons, saidg second named pistons being provided with outwardly opening valves and being formed with openings through which said first named piston rod is slidable, racks formed on said piston rodsl a transverse shaft, and pinions of different diameters meshing with the respective racks.

2. An air compressor comprising a shell provided intermediate its ends with an inlet opening and adjacent its ends with outlet openings, a power driven piston rod movable within said shell and reciprocating therein, pistonson said rod having passages normally closed by outwardly opening valves, a second piston rod, pistons on said second named rod provided with passages normally closed by outwardly opening valves 'and further provided with openings through which said first named piston rod is slidable, and means driven by said first named piston rod whereby to effect simultaneous movement of said second named piston rod and second named pistons at a different speed with respect to the movement of the first named piston rod.

3. An air compressor comprising a shell provided intermediate its ends with an inlet opening and adjacent its ends with outlet openings. a power driven piston rod movahle within said shell and reciprocating therein. pistons on said rod having passages normally closed by outwardly opening valves. a second piston rod, pistons on said second named rod provided with passages normally closed hy outwardly opening valves and further provided with openings through which said first named piston rod is slidahle. and means driven by said first named piston rod whereby to effect simultaneous movement of said second named piston rod and second named pistons at a different speed with respect to the movement of the first named piston rod. said means comprising rack and pinion mechanism connecting and transmitting movement between said piston rods.

In testimony whereof I affix my signature.

EMORY LEE BLEVINS. 

